The invention relates to a component carrier for holding at least one component, in particular for surface coating by electrodeposition.
DE 44 9 982 C1 has disclosed a holding device for coating components by electrodeposition. This device has a component carrier, which in its cavity along a contact surface has two extending magnets, the pole axis of which is oriented transversely with respect to the contact surface. The components are held on a contact surface of an electrically conductive component carrier by means of the magnet strips extending along the device, the electrically conductive contact surface extending on an outer side of the component carrier, which is of hollow design. The component carrier is designed as an elongate electrode for the surface coating of the components by electrodeposition. The components are arranged one behind the other in a row on a contact surface, a diaphragm which accommodates the components and positions then with respect to the contact surface being provided.
For surface coating by electrodeposition of the components accommodated by this holding device, the individual holding devices are arranged on, for example, a circular frame, in order to be immersed in the baths for coating.
Holding devices of this type have the drawback that only a small number of components can be accommodated for surface coating. The device, which is, for example, 1.20 m long, is very heavy and difficult to handle, requiring complex equipment with an extremely low capacity in order to carry out the coating, which requires a plurality of successive process steps.
Furthermore, this holding device has the drawback that, following the surface coating of armatures for injection nozzles, high-precision and high-sensitivity components of very low weight have to be removed from the holding device, while a considerable force is required for this purpose in order to overcome the magnetic holding force acting on the component in question. Consequently, the surface or coating of the components may be damaged as a result of the high levels of mechanical action required in order to overcome the magnetic holding force, with the result that this part has to be removed from production as scrap. Furthermore, the holding devices, which are of disproportionate size compared to the component size and are very heavy, have the drawback that, on account of bath liquids being entrained while the process steps for electrodeposition are being carried out, environmental problems may arise and, furthermore, a high consumption of bath liquid is required.
Therefore, the invention is based on the object of providing a component carrier in which, in order to improve the automation of the mounting and removal operation, the components can easily be mounted on and removed from the component carrier, while the entrainment of the bath liquid during the coating process is to be reduced. Furthermore, the risk of mechanical damage to the components during the mounting and removal is to be reduced, and during the coating process the required holding force for securely arranging the components with respect to the contact surface of the component carrier must be present.
The inventive design of the component carrier has the advantage that, at least during the removal operation, the adhesive force or holding force of the magnet acting on the component in question can be reduced. This makes it easy to lift the component off a contact surface without the risk of mechanical damage to the highly sensitive components, since extremely minor engagement or holding forces are required at least for removal of the component. The at least slight displacement of the component, of the holding magnet or a relative movement between the component and the holding magnet with respect to a holding position leads to a reduction in the resulting magnetic holding force with respect to the component, so that a lower force is required to lift off the component at least for removal. This effect is based on the fact that the further the component is positioned outside a resultant of the forces of the holding magnet, the greater the decrease in the field strength of the magnet and therefore also in the adhesive force. The components are advantageously formed from ferromagnetic material. The device according to the invention may advantageously be used for surface coating of the components by electrodeposition.
An alternative design of the component carrier according to the invention has the advantage that, on account of at least one magnetic interlayer which can be arranged between component and holding magnet, small masses are moved, a towing the resulting holding force of the magnet on the component to be reduced. Providing the magnetic interlayer makes it possible to achieve a shielding effect on the holding magnets with respect to the component, with the result that the adhesive force of the component with respect to the contact surface can be reduced at least for removal, thus ensuring that the component is easy to lift off. The shielding may also be advantageous for the mounting operation, so that the components can be placed gently on the contact surface. This also applies to the inventive design of the component carrier which will be described further in the specification along with other advantages of the invention.
Further advantageous embodiments of the invention will emerge from patent claims 2 to 42.
According to an advantageous configuration of the invention, the component carrier has a plurality of holding positions which are provided in an arrangement in the form of lines and columns with respect to a contact surface of the housing. Consequently, a large number of components, in particular in the case of small or extremely small components, can be accommodated within a confined space of a component carrier, with the result that the overall volume of the component carrier and the weight can be reduced by a considerable extent, thus simplifying and facilitating handling.
According to a further advantageous configuration of the invention, a holding magnet, which preferably comprises at least two magnet poles of opposite polarity facing the component, is provided for each holding position. This enables each component, in the holding position, to be assigned an individual holding magnet. This configuration has the advantage, in particular, that no magnetic material is present in the spaces between the individual components along a row of components, as is known, for example, from the holding device according to the prior art. Consequently, neutral zones which exert an extremely low holding action on the component through the resultant of the magnetic field lines can be formed between the individual holding magnets. Consequently, the maximum magnetic holding force can be reduced to a minimum or to zero. The resulting adhesive force of the individual holding magnet preferably lies in a holding position.
According to a further advantageous configuration of the invention, the individual holding magnets, which comprise at least two magnetic poles and have at least two magnetic poles of opposite polarity facing the component, are arranged in a row with one another, so that the polarities are identical along a row. As a result, it is possible, for example, to create a neutral zone, in which both one individual magnet and the other individual magnet exert a scarcely perceptible holding force on the component, can be created, for example, between these two individual magnets. A slight displacement of the component out of the neutral zone, which advantageously lies in the center of the two adjacent individual holding magnets, can lead to immediate orientation of the individual holding magnets with respect to the holding position, so that the resultant of the forces of the individual holding magnets lies in the holding position.
As an alternative to the embodiment described above, it is possible for the polarities of the individual holding magnets to be arranged alternately with respect to the contact surface.
According to a further advantageous configuration of the invention, the component carrier has an electrically conductive housing in which there is a carriage which accommodates the holding magnets and is arranged displaceably with respect to the holding position of the components. This can make it possible for the holding force acting on the components to be reduced and, if appropriate, cancelled out at the same time and to the same extent for all components as a result of the movement of the carriage. For specific applications, it is also possible, if necessary, for one or more holding magnets to be displaced in rows or columns with respect to the holding positions.
It is advantageous for a plurality of strips arranged parallel and next to one another to be provided on the carriage, which strips accommodate at least two magnetic poles to the left and right of the strip and at a distance from one another along the strip. This makes it possible to achieve a high density of the holding positions on a small contact surface of the component carrier, the distance between the individual magnets being in relation to the component size. It as advantageously provided for a gauge distance, i.e. the distance between the center axes of two components, to be at least 1.5 times the component diameter. This distance is advantageously twice the component diameter, in which case the displacement amounts to half the gauge distance.
According to a further advantageous configuration of the invention, the strips for accommodating the individual magnets are provided in recesses in a support frame of the housing, which accommodates the contact surface on its opposite surface. Consequently, the contact surface can be supported to a sufficient degree, since the holding position of the components lies in the recesses or between the webs of the support plate. The holding magnets are advantageously provided with a small air gap beneath the contact surface, so that it is possible to provide a contact-free and therefore low-friction arrangement of the carriage with respect to the contact surface. On account of the magnetic force which is active, it is possible, by means of the design of the support surface, to allow the contact surface to be arranged and held flat against the component carrier.
For mounting and removal on the component carrier, it is advantageous for the component carrier to be arranged on a bracket which on two opposite end faces has magnet elements which each have an opposite polarity in the direction of the component carrier. The carriage which is displaceable in the component carrier has, corresponding to the magnet elements of the bracket, on its end edges, magnet elements which are equipped with the same polarity and face toward the magnets of the bracket. Immediately after insertion, a repelling action can be achieved on one end side as a result of the identical polarity and an attracting action can be achieved on the opposite side, with the result that the carriage together with the individual holding magnets is guided out of a holding position. The amount of displacement can advantageously be determined by means of an adjustable stop, so that the holding magnets are arranged in an neutral zone for the purpose of mounting and removal of the components. It is advantageous for it to be possible for the carriage to move in both directions irrespective of the orientation in which it is inserted in the bracket. Alternatively, it is possible for the component carrier to be oriented with respect to the bracket. This could be the case, for example, if a slight attraction force is desired for the mounting operation, so that the components are positioned flat and in full contact with the contact surface and are to be attracted slightly during the positioning operation. In an application of this type, the amount of displacement in one direction is smaller than the amount provided for the removal operation.